In commonly used public mobile communication systems the mobile devices are wirelessly connected to base stations and a communication between the mobile devices is done via at least one base station. The mobile devices, which will be called in the following also mobile terminals or simply terminals, may comprise for example mobile phones, especially so-called smartphones, personal digital assistants, mobile music players, tablet computers, laptop computers, notebook computers or navigation systems. The communication technologies of the mobile communication systems are specified by for example the 3rd Generation Partnership Project (3GPP) and the Long Term Evolution (LTE) standards. The principle is illustrated in FIG. 1. FIG. 1 shows two base stations 10 and 11 and eight mobile devices 21-28. Base station 10 provides a network communication cell 12 and base station 11 provides a network communication cell 13. A wireless or wired communication is provided between the base stations 10 and 11. The mobile devices 2124 are located within cell 12 and the mobile devices 25-28 are located within cell 13. A communication between two of the mobile devices 21-28 is accomplished by communication between the mobile device and the base station related to the cell in which the mobile device is located. In a communication between one of the mobile devices 21-24 and one of the mobile devices 25-28 both base stations 10 and 11 are involved. When a mobile device is moving from one cell to another cell, the mobile device registers at the base station assigned to the newly entered cell. The event of a mobile device moving from one cell to another cell is also called handover or cell change.
As one part of possible additions to the 3GPP standards for future versions and releases of the LTE and possibly WCDMA (Wideband Code Division Multiple Access) standard, it is considered to include a functionality for a so-called device-to-device communication. The device-to-device communication allows an information transmission directly between two mobile devices within a certain proximity. For example, in FIG. 1 a direct device-to-device communication could be performed between the mobile devices 22 and 23 or between the mobile devices 25 and 26 when the distance between these mobile devices is shorter than a radio transmission range of the mobile devices.
Furthermore, as part of the device cell change support functionalities, which are also called terminal mobility support functionalities, in the 3GPP standard, each base station is supposed to have knowledge about the identity of neighbor cells within the same geographical area. Referring to FIG. 1, base station 10 is supposed to have knowledge about the neighboring base station 11 and vice versa. The base stations can therefore publish candidate neighbor cell lists to the mobile devices in order to inform about suitable cells to analyze in case current signal quality is too low and the mobile device needs to change the cell. These cell lists can be filled in manually to each base station of each cell by an operator. Furthermore, there is an improved functionality included in the WCDMA and LTE standards which is called Automatic Neighbor Reporting (ANR). With the Automatic Neighbor Reporting the cell lists in the base stations can be updated by means of measurement reports from connected mobile devices. For example, a mobile device may detect available and suitable cells in a geographical area around the mobile device. This information may be transmitted to the base station the mobile device is currently registered at to update the neighbor cell lists in the base station. In return, the mobile devices receive the updated neighbor cell lists from the base station in order to be able to find suitable cells in case of a cell change and to avoid interference from unknown cells. However, in case the Automatic Neighbor Reporting functionality is not implemented or is updated too slowly compared to the rapid changes that may occur in the network, there may be new cells or other changes in the neighborhood which are not noticed and considered in the cell lists and thus the mobile devices are not aware of.
Therefore, there is a need for an improved neighbor cell reporting functionality.